Ultralight and highly compressible Janus mullite nanofiber sponge for oil–water separation

The development of nanofiber sponge materials with three-dimensional structures, high porosities, and large specific surface areas is crucial for the rapid separation of water-in-oil emulsions. In this study, we fabricated Janus mullite nanofiber (MNF) sponges with efficient oil–water separation performance using a novel combination of electrostatic-assisted solution blow spinning ( E -SBS) and in situ growth. MNF sponges weighing 0.074 g were subjected to 100 compression cycles, with the stress reducing to 85.6 % of its initial value after impregnation with ZIF-8 nanoparticles and OTS. Consequently, the MNF sponges changed from hydrophilic to hydrophobic, and after 20 separation experiments, they still maintained high separation fluxes for oil–water mixtures and emulsions, achieving 7959 and 1803 L m −2  h −1 , respectively. Moreover, the preparation process of the MNF sponges is environmentally friendly, causing no environmental pollution. Therefore, Janus MNF sponges show great potential for applications in oil–water separation.